This invention relates generally to refrigerators, and more particularly, to control systems for refrigerator quick chill and thaw systems.
A typical household refrigerator includes a freezer storage compartment and a fresh food storage compartment either arranged side-by-side and separated by a center mullion wall or over-and-under and separated by a horizontal center mullion wall. Shelves and drawers typically are provided in the fresh food compartment, and shelves and wire baskets typically are provided in the freezer compartment. In addition, an ice maker may be provided in the freezer compartment. A freezer door and a fresh food door close the access openings to the freezer and fresh food compartments, respectively.
Known refrigerators typically require extended periods of time to cool food and beverages placed therein. For example, it typically takes about 4 hours to cool a six pack of soda to a refreshing temperature of about 45xc2x0 F. or less. Beverages, such as soda, are often desired to be chilled in much less time than several hours. Thus, occasionally these items are placed in a freezer compartment for rapid cooling. If not closely monitored, the items will freeze and possibly break the packaging enclosing the item and creating a mess in the freezer compartment.
Numerous quick chill and super cool compartments located in refrigerator fresh food storage compartments and freezer compartments have been proposed to more rapidly chill and/or maintain food and beverage items at desired controlled temperatures for long term storage. See, for example, U.S. Pat. Nos. 3,747,361, 4,358,932, 4,368,622, and 4,732,009. These compartments, however, undesirably reduce refrigerator compartment space, are difficult to clean and service, and have not proven capable of efficiently chilling foods and beverages in a desirable time frame, such, as for example, one half hour or less to chill a six pack of soda to a refreshing temperature. Furthermore, food or beverage items placed in chill compartments located in the freezer compartment are susceptible to undesirable freezing if not promptly removed by the user.
Attempts have also been made to provide thawing compartments located in a refrigerator fresh food storage compartment to thaw frozen foods. See, for example, U.S. Pat. No. 4,385,075. However, known thawing compartments also undesirably reduce refrigerator compartment space and are vulnerable to spoilage of food due to excessive temperatures in the compartments.
Accordingly, it would further be desirable to provide a quick chill and thawing system for use in a fresh food storage compartment that rapidly chills food and beverage items without freezing them, that timely thaws frozen items within the refrigeration compartment at controlled temperature levels to avoid spoilage of food, and that occupies a reduced amount of space in the refrigerator compartment.
In an exemplary embodiment, a control system is provided for a refrigerator including a quick chill and thaw system. The quick chill and thaw system includes a modular air handler for producing convective airflow within a slide-out sealed pan at temperatures above and below a temperature of the fresh food compartment to achieve both rapid chilling and safe thawing of items in the pan.
More specifically, the air handler includes a first damper element adapted for flow communication with a supply of air, such as a refrigerator freezer compartment through an opening in a center mullion wall of the refrigerator so that a supply airflow path of the air handler is in flow communication with the first damper element. A fan in the air supply path discharges air from the air supply path into the pan, and a re-circulation airflow path allows mixing of air from the pan with freezer air in the supply airflow path for quick chilling. A heater element is located in an air handler return duct for warming air in the air handler for thawing. A temperature sensor is located in flow communication with at least one of the re-circulation flow path and the return flow path for temperature responsive operation of the quick chill and thaw system.
The control system for the quick chill and thaw system comprises an electronic controller coupled to the operable components of the air handler. The controller is configured to adjust the air handler components to produce a constant temperature airstream in the sealed pan, maintain a first constant temperature airstream in the pan to execute a chill mode when selected by a user, and maintain a second constant temperature airstream in the pan to execute a chill mode when selected by a user.
A chill algorithm is executable by the controller to maintain desired temperatures in the sealed pan, and the controller is responsive to temperature feedback from temperature sensors located in the air handler and re-adjusts operation of the air handler as necessary. Thaw algorithms are also executable by the controller and in one aspect, a heat output of the heater is monitored to sense a state of a frozen package to be thawed, and the controller determines an end of a thaw cycle by comparing the monitored heat output to a reference heat output.
An adaptive electronic control scheme is therefore provided to efficiently chill and safely thaw food and beverage items in a space saving quick chill and thaw system.